Decommissioning Out-Of-Service Water Wells to Protect Water Quality

Picturesque windmills, like this one near Sand Creek, dot the Nebraska countryside, but wells below them can deteriorate and contribute to contamination of the underlying groundwater aquifer if not properly abandoned (photo: Dave Shelton).

UNL Extension agricultural engineer Dave Shelton (far right) helps decommission an out-of-service water well. Doing this job correctly contributes to better water quality for everyone (photo: Dave Shelton).

By David P. Shelton
Extension Agricultural Engineer
UNL Haskell Agricultural Laboratory

Windmills dot the Nebraska landscape – but did you ever stop to think that this picturesque scene could be contributing to groundwater contamination?

Not the windmill itself, but perhaps the well below. Often, these wells are deteriorating and no longer used, but the well shaft is still a direct connection from the ground surface to the underlying aquifer. This can allow surface runoff to flow directly to the water-bearing zones, often carrying organic wastes, fertilizers, and other chemical residues such as pesticides and petroleum products into the groundwater. Small animals can fall into these wells, further adding to the contamination. Contaminants that enter an old, out-of-service well can migrate to in-service water supplies such as a new well on the property, or a neighbor's well. Once groundwater is contaminated, it is difficult, if not impossible, to clean up, and the process is always expensive.

Unused wells, especially those that are old and/or in disrepair, or that do not meet current standards as an inactive well, pose a major threat to groundwater quality and represent a serious threat to human health and safety. State law defines these as illegal wells.

There are thousands of these wells on farmsteads, acreages, and other rural areas throughout the state. Early Nebraska settlers found that many areas had relatively abundant groundwater that could be obtained fairly easily. In many situations, it was common to have more than one well on each farmstead because it was easier to construct a well at the point of use rather than develop a central water well and distribution system. Farm consolidation, rural electrification, and general modernization took many of these old wells out of service. Also, throughout the years when a new well was drilled, the owner often neglected to properly decommission the old well.

Not all out-of-service wells are located on farmsteads or in rural areas. There likely are hundreds, and possibly thousands, located in communities throughout the state. In the early development of communities, most households and businesses had an individual water-supply well. Most of these water wells have since been replaced by community water-supply systems, but in some cases, the old wells were not properly decommissioned.

While a windmill tower can be an almost sure sign, wells can be present at many other locations too. Some signs that an old well might exist include: concrete pads where the legs of a windmill tower once stood; depressions where an old well pit or the walls of a dug well may have collapsed; an old stock tank in an over-grown area; a small area that is fenced off, especially if there are also pipes sticking out of the ground; flat stones, a concrete slab, old boards, metal sheets, or other items that could be covering an old well shaft; and many others. Sometimes there are no signs. For example, one landowner discovered a 36-inch diameter, 50-foot deep dug well when the front wheel of his tractor dropped into it. He did not know that this well was there, despite having grown up on that farm. (This well has now been properly filled and sealed.)

Nebraska regulations require that illegal wells be decommissioned following the requirements found in Title 178, Chapter 12, Regulations Governing Water Well Construction, Pump Installation and Water Well Decommissioning Standards of the Nebraska Department of Health and Human Services. With only one exception, Water well decommissioning must be carried out or supervised by an individual with a valid Nebraska Water Well Standards and Contractors’ license.

The decommissioning process includes removal of well equipment (pump, piping, etc), disinfection, sealing, filling, capping, and reporting. The cost of decommissioning a well depends on several factors including accessibility, construction technique and materials, diameter, depth, condition, and contractor travel distance. Generally this is not particularly expensive. For example, in conjunction with a special water quality educational program in the Shell Creek Watershed in northeast Nebraska, 27 out-of-service wells were decommissioned during 2005, 2006, and 2007 at an average cost of $388 per well. Most of these wells were small-diameter domestic and livestock wells, although at least two were deeper, larger-diameter wells that cost approximately $850 and $1100 each.

Because of the importance of protecting water quality, nearly every Natural Resources District (NRD) offers an attractive incentive to assist well owners with the cost of decommissioning.  Payment rates vary by NRD, but typically these programs will pay for 60 to 75% of the costs. With these cost-share payments, out-of-pocket expense to the well owner will often be on the order of $100 - a small price to pay to help assure that water quality and human health and safety are protected.

Additional information on well decommissioning, links to the NRDs, and many other water-related topics can be found on the water.unl.edu website.